Transportation devices in the sense of the invention are escalators and moving walks with a plurality of tread units, escalator steps or moving-walk pallets, which are joined to form an endless transporter. Users of the transportation devices stand on tread surfaces of the tread units, or stand or walk on the moving walk-pallets in the same direction of travel as the transportation devices themselves.
On escalators, the escalator steps form tread units, hereinafter referred to as “steps”, and on moving walks the moving-walk pallets form step units, hereinafter referred to as “pallets”. Escalators have a relatively large angle of inclination to overcome relatively large height differences such as appear between full building stories or greater. Moving walks run horizontally, or at a slight inclination, but generally with a smaller angle of inclination than escalators.
Such transportation devices typically contain step chains or pallet chains, by means of which the steps or pallets are moved in the direction of transportation. Hereinafter, reference will only be made to step chains, but this should be understood to refer also to pallet chains. These step chains are driven, and are provided with so-called rollers at equal intervals. The rollers roll or travel along tracks. In the area of the ends of the transportation devices, the step chains with the rollers pass around sprockets, or reversers, and thereby execute a change in direction of 180 degrees.
A transportation device with step chains or pallet chains is known from patent application DE-100 63 844. In that patent application, the primary objective is to reduce the number of chain elements, or chain links, that are used per step or pallet.
It is regarded as a disadvantage of transportation devices hitherto that the step chains, along with numerous rollers, are composed of many individual parts that are expensive as well as cost- and work-intensive. On the other hand, the step chain, along with the elements mounted on it, is one of the most important components of the transportation system of a transportation device, and certain changes to this complex drive system or transportation system can have undesired consequences, such as reduced ride comfort and possibly also uneven running or increased noise production.
Objects of the present invention are thus to create a drive system of the type stated in which such disadvantages stated are avoided, and which nevertheless enables smooth, jerk-free running, is not prone to faults, and has a long service life; and
to create a transportation device that is equipped with such a transportation or drive system.